Please make sure you are entering the user name, registration code and number of users exactly as this information appears on your license letter mailed with the software or in the e-mail sent to you after your order was processed:

Name: {enter your name exactly as it appears here}
Code: {enter your registration code exactly as it appears here, it is case sensitive}
Users: {enter the number of licensed users exactly as it appears here}

If any of this information is entered differently than how it appears in your license letter or e-mail, the software will continue to run as the trial version. The trial version of version 6 will enable with the registration information. To enable the trial version, open the program and go to Help | Enter Registration Info...

For versions released before version 6, the number of users is not relevant.